The Marketo↔Salesforce sync is the most-misunderstood piece of B2B martech. Marketing teams treat it as a black box. Sales teams blame it for everything. The truth is in the middle: it is predictable once you understand a few rules.
Direction matters
Most fields sync bidirectionally, but Marketo is the system of record for engagement data and Salesforce is the system of record for ownership data. Decide once, per field, which system wins — and write it down.
Field types are not a detail
Picklists in Salesforce do not auto-update Marketo. Multi-select picklists are particularly fragile across the sync. Choose simple text or boolean wherever you can. When you need picklists, document the canonical values in both systems.
Failures are loud if you instrument them
Both platforms emit sync errors. Most teams never look. Pipe a daily count of sync errors into a dashboard your MOPs lead opens every morning. A spike from 0 to 200 means something just broke — and it is almost always cheaper to fix on day one than day thirty.
Drift is the silent killer
Run a quarterly reconciliation: random sample 100 leads, compare key fields across both systems, and document differences. The drift you find is the drift your reporting is already hiding.